Motor construction for mechanical horns



April '1, 1924. v 8 1,488,786

' H. C. GRANT MOTOR CONSTRUCTION FOR MECHANICAL HORNS Filed "8y 5, 1922 awn W04.

Ear/"y Kira/1f Patented Apr. 1, 1924.

UNITED STATES PATENT OFFICE.

mar C. GRANT, OF BAYONNE, NEW JERSEY, A SSIGNOR TO KLAION COMPANY, A CORPORATION OF DELAWARE.

MUIOB CONSTRUCTION FOR MECHANICAL HORNS.

Application filed May 3, 1922. Serial No, 558,163.

To all whom it may concern:

Be it known that I, HARRY C. GRANT, a citizen of the United States, and resident of Bayonne, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Motor Constructions for Mechanical Horns, of which the following is a specification.

My present invention is particularly designed for use in connection with the motor construction invented by Duncan A. Mc- Connell and set forth in his application Serial No. 558,108, filed May 3, 1922.

While certain details of my invention are adapted for use in other re ations, it primanly concerns a brush holder adapted for use in combination with a bridge piece which affords a front bearin for'the armature shaft in such a motor. he nature and objects of the invention will be more fully understood from the following descri tion in connection with the accompanying rawin, in which ig. 1 is a side elevation with the casm broken away to show the operating parts 0 the instrument.

Fig. 2 is a section on the broken line 22,

fieferring to these drawings, the projector 1 is secured to front casing 2 by flange 3 and rib 4, and also by soldering or brazing, if desired. The rear casing is an integral drawn shell or cup comfirising a cylindrical rtion 5, rear end we 6, and referably also, the diaphragm clamping ange 7 is integral. The diaphragm 8 is secured between the clampin members by screws 9, preferably passing oosely through the front casi 2 and secured by nuts 10 which may be liifid from unscrewing by s ring locking washers 11 of an known or esired tglpe.

The rear wall has a punched and awn cylindrical extension 13 which constitutes a housing for the bee 14 which may be threaded therein and nut 15. l

punched and drawn to the shape shown in secured by lock' The sheH,5, e, is ofiron or-mild m1 of such quality that it is capable of beingthe drawings and also capable of being util1 zed as the magnetic circuit between the pole pieces of the motor. The pole pieces are preferably located near the rear wall of the cup and there is a partition or bridge piece 31 across the cup near the open end thereof forming the front bearing for the armature shaft and this bridge piece is preferably of magnetic material forming of the magnetic circuit of the motor The peri heral wall'is flattened in to form an inward y projecting boss 18 with a flat top 19 forming a good seat for the core pieces 20 and a flarlng base as at 21. The outward flaring curvature of the boss away from the base of the core iece seems to make the metal cup more near y a magnetic unit wlth the cores, affording somewhat easier and natural lines of flow of the magnetic energy.

The electromagnets have soft iron cores 20, each having a reduced shank 23, whereby it is riveted into extremely intimate engagement with the surface 19 of one of the shell bosses. The cores are provided with the usual therewith or may be se arate pieces rolled to shape and cut up, or t ey maybe stamped directly from sheet metal. .When the pole pieces are separately formed, they may be secured to the cores 20 by shanks, riveted as at 24.

In practice the cores and pole pieces pole pieces, which may be integral thereon and the s anks 23 inserted through the boss openings at 19. A cylindrical mandrel'of the exact diameter. required for the field of the motor may be then inserted with its axis exactl centered on the axis of the armature sha bearing 14. The riveting operation is, then performed preferably by (he presses acting simultaneously on both pole pieces so as to apply balanced thrust throughthe cores upon t e intervening mandrel. The pressures required for riveting are suificient to fit themetal of the case to the diameter of the mandrel, with great accuracy.

The motor-armature 27, commutator 28,

and shaft 29, may be of the usual construction. The rear end of shaft 29 rests in the bearing 14. The forward bearing for shaft 29 is in transverse member, preferably of magnetic material, which may be either a wall or merely a bridge piece 31, extending diametrically across the cup and secured in position by screws 32, screwing down on lock washers 33.

This bridge piece 31 carries the brush holders 34: which consist of blocks of insulating material, such as condensite or bakelite molded to shape under heat and pressure Each has a square recess of suitable depth and cross section to afford a sliding fit for the brushes 35 and parallel side flanges. which accurately fit against the sides of bridge piece 31. A convenient way of forming the recess for accurate sliding fit of brushes 35 is to make one side wall 36 removable so that the recess may be molded as an open slot and the cover 36 afterwards applied and the whole secured by rivets 30, 30, extending through cover, brush holder and bridge piece.

The circuit wire from the field coils is preferably twisted in the form of a helix as at 37, the length and diameter of the helix being such that it loosely fits the brush holding recess. The axis of the helix is crosswise of the recess and is parallel with the axis of the commutator upon which the brush bears, consequently the surface of the helix forms a sort of rocker bearing which affords a support across the width of the rear face of the brush. The surface of the helix being made of the round wires, bears upon the rear face of the brush at a multiplicity of points tending to slightly wear and cut into the brush thereby maintaining and renewing perfect electric contact even under extreme adverse conditions,- as where lubricating oil finds its way into the brush holder. The helix forms a head on the end of the circuit wire, and the uncoiled or shank portion of the latter extends out through a relatively narrow slot 38, which latter need be only wide enough to permit easy passage and sliding fit of said circuit wire. The helical contact head is resiliently forced against the base of the brush by means of the usual follower spring 39. If desired, the helix may be a tight coil with the sides of adjacent turns in contact, and it may be dip ed in solder or tinned to make it. more rigi The parts may be assembled in the brush holders simply by removing the cover 36' and inserting them laterally in the position shown. In most cases, however, it will be simpler to shift the commutator out of position, insert follower spring 39, insert the helix 37 with the circuit wire projecting through slot 38, insert the brush, force it back to sufiiciently compress the follower spring, and finally insert the commutator in position between the ends of the brushes.

The diaphragm wear piece consists of a circular stampin having an eccentric portion projecting rom one side thereof and formed with a wear piece comprising an incline leading up to a more or less pronounced tip or edge which extends substantially radial to the axis of the wear piece, opposite to and parallel with the cam projections on the rotor 40. The rotor is preferably in the form of a hard steel cup as shown, and is secured in position by a stud screw 41 shown in dotted line, Fig. 1.

The wear piece is secured by a rivet 42 which extends througha square aperture 43 in the center of the diaphragm, through a cushionwasher 44 which is preferably made of the same steel as the diaphragm, and through a front washer 45 which is preferably a cup shaped stam ing as shown. The diaphragm is cushione from contact with the metal clam in members by elastic washers 12, 12, pre era ly of cork composition.

I claim:

1. In a dynamo electric machine of the class described, a shell or on of magnetic material and a bridgepiece 0 ma etic material connecting opposite sides 0 the shell and affording a front bearing for the arms.- ture shaft and, on opposite sides of said bearing, aligned brush holders, each brush holder having a bod portion molded from insulating material, ormed with side flan embracing the side faces of said bri ge piece and tension members securing said brush holders to said bridge piece.

2. In a dynamo electric machine of the class described, a shell or on of magnetic material and a bridge piece 0 ma etic material affording a front bearing or the armature shaft and, on opposite sides of said bearing, aligned brush holders, each brush holder having a body portion molded from insulating material, with the slideway in the form of an open slot, a cover-piece of insulating material for said body portion and rivets extending throu h said cover and body portion and said bri ge piece.

3. In a brush holder, 0. block of insulating material formed with a slidewa having a brush and follower sprin fitted t erein, and formed with a lateral s 0t communicating with said slideway, in combination with a circuit connection comprising a conductor projecting laterally throu h said slot and provided with a terminal ead within said recess large enough to prevent withdrawal through said slot.

Ill

4. The combination specified by claim 3, I

with the further feature that the enlar ll with the further feature that said head is located between the base of the brush and 1 the follower spring and is formed as a helically coiled end of said conductor. Signed at Bayonne, in the county of Essex and State of New Jersey, this 5th day of March, A. D. 1922.

. HARRY C. GRANT. 

